It looks like a Rock Anemone, a.k.a. Flower Anemone. Here's some info I found on them. Hope this helps and someone correct me if I'm wrong!!
The Rock Flower Anemone, also known as the Rock Anemone, is a member of the Phymanthidae family. Originating from the Caribbean, these anemones are found in a wide array of colors, with the oral disc often being a different color than the rest of the anemone. The oral disc lacks tentacles, and the tentacles are often beaded in appearance.
The Flower Anemone can live singly or in groups. They prefer to live on shaded, vertical rock walls, or within the substrate. They will bury most of their body in the sand, with only the oral disc and tentacles showing. These are fairly hardy anemones that will adapt to a wide variety of lighting conditions. These anemones tend not to wander about the aquarium and are a great addition to a reef aquarium.
The Flower Anemone is a carnivore, and requires meaty foods to survive. Offer mussels and freshly chopped fish meat, as well as high quality frozen foods. Adding iodine and trace elements to the aquarium will help the Flower Anemone thrive.
